1. Field of the Invention
This invention relates to tamperproof and moisture proof enclosures for data readout devices which are located remote from a measuring device, such as utility meters which are usually located within the house, the readout device being located on an exterior wall of the house.
2. Description of the Prior Art
In northern latitudes it is customary to locate utility meters, particularly water meters, within the residence so as to render the meters unaffected by the prevailing climate. However, such a location for these meters presents problems to the utilities in obtaining the necessary periodic readings on the meter registers showing consumption of the water or other utility. Often the owners of the residence are not present when the meter reader is making his rounds or, in some cases, even when the residence is occupied, the occupant is reluctant to allow a stranger into the house. As a result, remote readout devices have been developed by various meter suppliers which are located exterior to the house but have an electrical or other connection with the meter located inside of the residence so that the meter reading is trasmitted from the meter to the remotely located readout device outside the residence.
One such system which is currently available on the market is shown in the U.S. Pat. No. 3,748,654 to Sutherland. In the system disclosed in that patent, the digital registration apparatus driven by the meter which is located within the residence produces a coded signal representative of water consumption which signal is transmitted to a circuit board which has output terminals adapted to be engaged by a receptacle in a portable readout gun carried by the meter reader. The meter reader is also provided with a data accumulating storage device to which the gun is electrically connected. After a removable cover is removed from the enclosure, the receptacle on the gun is inserted into the enclosure and engages the terminals on the circuit board. When the data accumulating device is energized, the reading at the meter is transferred from the meter through the readout station into the data accumulating device where it is accumulated and recorded by some well known convenient manner, such as tapes.
The enclosure disclosed in that patent is comprised of a base plate with a cover each of which have cooperating sealing means which provide a moisture proof chamber within the enclosure when the cover is on the base plate. It is necessary to prevent unauthorized access to the interior of the enclosure, otherwise the circuitry within the enclosure could be altered by some knowledgeable person to provide a spurious readout. In the enclosure shown in U.S. Pat. No. 3,748,654, the cover is secured to the base plate by means of four brass screws which are accessible from the exterior of the enclosure. A conventional means of preventing unauthorized access to the interior of the enclosure in such a design would be to provide holes in the screws through which a wire is passed, the ends of the wire being connected by a lead seal impressed thereon by the utility. Thus, removal of the cover would be impossible without affecting integrity of the seal.
While the cover and the base plate may be made of relatively inexpensive plastic material, such as a modified styrene based plastic, it is necessary that the screws be of some metallic material and preferably of brass to prevent corrosion. Such a means of securing the cover to the base plate is relatively expensive and, in order to to minimize the cost of producing and installing the enclosures while still maintaining security against unauthorized access to the interior, the instant invention provides an improved means for securing the cover to the base plate.